The present relates to replaceable ink cartridges used with inkjet printers in general and to the preventing the use of non-genuine ink cartridges in particular.
Inkjet printers use cartridges filled with ink for the production of the printed pages. Except for printing paper these cartridges are the major consumable item used with the printers and need replacing on a regular basis. It is in the interest of the printer manufacturers to ensure that only their own original replacement cartridges are used. However, there is a large secondary market for the ink itself either sold on it""s own for the consumer to fill the used up cartridge and for non-original replacement cartridges refilled with ink by those ink-manufacturers. These non-original ink sources can cause malfunction of the printer or even permanent damage.
Manufactures of thermal bubble print heads utilize expendable cartridges which include the thermal head as part of the cartridge. The thermal head as well as the cartridge is thus disposable, and can not be reused.
Alternatively, other printers use heads which are a permanent part of the printer. The type of cartridge used with permanent head printers comprises an ink bag for storing the recording ink. U.S. Pat. No. 5,157,421 to Kithara and EP Patent No. EP 0 661 160 to Nishioka, for example, describe replaceable ink jet cartridges for use with ink jet printers.
A disadvantage of ink bags (from the manufacturer""s point of view) is that they are relatively easy to refill and imitate. The manufactures of original equipment are, thus interested in preventing other sources from refilling the cartridges and copying or faking their original cartridges.
An object of the present invention is to provide an ink cartridge which cannot be tampered with and which cannot be refilled by outside sources, thereby overcoming the limitations and disadvantages of existing cartridges.
A further object of the present invention is to provide an ink cartridge whose authenticity can be checked so as to deter the production of non-authorized copies.
There is thus provided, in accordance with a preferred embodiment of the present invention, an ink cartridge which includes a rigid housing and a flexible ink storage bag inserted within the housing. The storage bag is connectable to the ink supply line of a printer by means of a hollow needle. The storage bag is impenetrable by the needle or similar when the storage bag is depleted of ink.
Furthermore, in accordance with a preferred embodiment of the present invention, the housing includes upper and lower chambers connectable together. In addition, the housing further includes an outlet port for connecting the housing to the printer.
Furthermore, in accordance with a preferred embodiment of the present invention, the hollow needle includes an angled sealed point formed in one end thereof.
Furthermore, in accordance with a further preferred embodiment of the present invention, the ink cartridge includes a metal element placed on top of the ink storage bag so that the metal element descending as the ink storage bag is emptied. In addition the metal element includes an annulus formed therein and is also composed of a ferrous material.
Furthermore, in accordance with a further preferred embodiment of the present invention, the printer includes a magnetic sensor proximate to the bottom of the lower chamber for sensing the presence of the ferrous metal element thereby to indicate the depletion of the storage bag.
In addition, in accordance with a further preferred embodiment of the present invention, the ink cartridge further includes an indicator representing a logo attached to the exterior face of the housing. The indicator is composed of conductive material responsive to electro-magnetic fields and the printer includes a detector for detecting the form of the indicator.
Preferably, the detectable metal logo is placed on a mechanically formed raised or recessed shape of the logo, and a negative shape is included in the housing of the printer. Thus, it is necessary to insert the raised mechanical form into the recessed mechanical form of the logo, in order to fit the cartridge to the printer.
Furthermore, the ink cartridge includes a processing unit which may be coupled to the central processing unit of the printer.
Additionally, there is also provided, in accordance with a preferred embodiment of the present invention, a method for verifying the authenticity of an ink cartridge. The ink cartridge has a processing unit coupled thereto and the method includes the steps of:
a) installing and connecting the ink cartridge to a printer having a central processing and control unit (CPU) connected thereto;
b) the CPU sending a randomly generated number (xe2x80x9ccodexe2x80x9d) to the installed ink cartridge;
c) the CPU performing a first encryption algorithm on the code;
d) the cartridge processing unit performing a second encryption algorithm on the code;
e) comparing the resulting first and second encryption algorithms; and
f) indicating an error if the resulting first and second encryption algorithms are not identical.